The invention relates to an apparatus for metering small amounts of a low boiling liquefied gas.
Very small amounts of low boiling liquefied gases are very difficult to meter, since the accumulated liquid gas is, in general, under pressure and has a temperature which corresponds to the boiling pressure or which lies above the boiling temperature at atmospheric pressure. The gas which is formed during pressure release in the supply line or at the discharge opening, therefore, again and again interrupts the continuously running liquid flow so that a uniform metering becomes impossible.
The problem of metering small amounts of low boiling liquefied gases occurs particularly in packaging various types of foods in which, for example, nitrogen is the inert gas or in which the liquefied gas has to profuse a certain internal pressure after closing the wrapping. A process for metering small amounts of low boiling liquefied gases is known from German Offenlegungschrift No. 25 48 745 according to which an absorbent body of a certain size is soaked with the low temperature liquefied gas. The absorbent body is then placed in the wrapping or the container which are subsequently closed. A very accurate metering of the liquid gas is indeed attained with this process, however, a foreign body is inevitably present in the package. This is not desirable in most cases.